Ignition system for internal combustion engine



Aug. 13, 1963 c. L. WOOD 3,100,479

IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINE Filed Aug. 9. 1960 2 Sheets-Sheet 1 l5 l9 l6) oouw l7 s I9 I WW; l7

IS A

l9 W as I?) INVENTOR CARL L. WOOD BY Z ATTORNEY Aug. 13, 1963 c. L. WOOD 3,100,479

IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINE Filed Aug. 9. 1960 2 Sheets-Sheet 2 I I I I I II;

INVENTOR CARL L. WOOD TEE E.

United States Patent ice 3,130,479 Patented Aug. 13, 1963 Nevada Filed Aug. 9, 1960, Ser. No. 43,450

14 Claims. (Cl. 123-448) This invention relates to an electrical ignition system for an internal combustion engine.

According to prior art practice, electrical ignition systems for internal combustion engines have generally relied on a battery energized ignition coil which. employed me chanical switching devices to energize the ignition coil and supply a high potential to a spark plug for igniting the fuel mixture. With multi-cylinder engines, it is the conventional practice to employ a single ignition coil along with a mechanical distributor switch whereby the voltages built up in the. ignition coil are applied to the spark plug of each cylinder in sequence. Such prior art practice possesses certain inherent disadvantages with regard to mechanical wear of the many moving parts, imperfect timing and incomplete combustion.

The fuel mixture in the cylinder of an internal combustion engine must be ignited early enough to insure effective burning throughout the entire combustible mix ture at the point of maximum compression or power will be needlessly lost. With the prior art mechanical devices, timing whereby the spark is ignited at exactly the right point is achieved only approximately. With multi-cylinder engines employing a. single ignition coil and a distributor switch, the very short duration of time between the firing of one cylinder and the firing of the next succeeding cylinder is often insufficient for complete saturation or build-up of the ignition coil and, accordingly, a relatively weak sparkis produced. Further, arcing between mechanical breaker points and distributor points for internal combustion engines wherein mechanical switching devices, including a mechanical distributor, and their substantial number of moving parts are eliminated or substantially reduced and wherein ignition of the fuel mixture in each cylinder is accomplished at the optimum time with a hotter spark.

Other objects and advantages of the instant invention will become more apparent from a review of the following detailed description when taken in conjunction with the appended drawings wherein:

FIG. 1 diagrammatically illustrates an ignition circuit in one embodiment of this invention for application to a multi-cylinder, internal combustion engine wherein the electronic valves employed therein are transistors; and

FIG. 2 diagrammatically illustrates an ignition circuit in a further embodiment of this invention for application to a multi-cylinder, internal combustion engine wherein the electronic valves employed therein are triode tubes.

Referring now to the drawings and in particular to FIG. 1, it will be seen that the apparatus of the present invention includes a source of suitable potential, such as a conventional automobile storage battery 1. Storage battery 1 is connected to lines 2 and 3 used to supply current to the spark plugs 6 and accompanying ignition circuits for each cylinder of the engine. The connection to line 3 is through line i and a conventional automobile ignitionswitch 5.

Although FIG. 1 illustrates the applciation of the invention to six-cylinder engines, it is to be understood that this invention may be applied to engines having more or less than six cylinders. The ignition circuit A for each spark plug 6 is identical and thus a description of one will suffice for all. 1

Each ignition circuit A comprises a spark plug 6, a transformer 7, an electronic valve or transistor lit, a pressure sensitive cell 11 and a potentiometer 14.

Spark plug 6 is connected to line 2 through line 15 and to line 3 through line 16, secondary winding 9 of transformer 7 and line 17. The high voltage required to cause spark plug 6 to spark is supplied by inducing a high voltage pulse in the secondary winding 9 of transformer 7. The high voltage pulse is brought about by interrupting or cutting off a current which normally flows through the primary winding 3 of transformer 7 by means of the electronic valve or transistor 10. Cur rent is supplied to primary winding 8 of transformer '7 from line 2 through line 18, transistor itiand line 19 and from line 3 through line 17. The capacitor 13 is connected across or in parallel with transistor 10 to prevent damage to transistor ll when the circuit is interrupted. The current supplied to primary winding 8 is controlled by means of a negative bias voltage applied to a conventional control connection 20 of transistor 16 and the current supplied to primary winding 8 is cut off by raising the bias voltage applied to control connection resistance in pressure sensitive cell 11 to decrease, thus increasing the bias voltage on transistor 1%. Potentiometer 14 is provided in the circuit to adjust the level of the bias to the point whereby bias voltage will reach cut-off at the exact time the cylinder piston 5d of the engine, and shown somewhat schematically in the drawings, reaches the point in its upward movement where a spark is needed.

One type of suitable pressure sensitive cell 11 is illustrated cross-sectionally in FIG. 1 of the drawing. This device can comprise a metal tube 24 which leads to the combustion chamber of a cylinder and a metal sleeve 25 ailixed' to the upper part of tube 24. A cap 26 ofsuitable ceramic material is fixedly mounted in sleeve 25 and a small metal receptacle 27 containing carbon particles 28 is dependingly aflixed to cap 26. Electrodes 29 and 30 extend through cap 25 and contact the particles 28. The electrode 29 is connected through terminal 31 to line 23 and to control connection 200i transistor 10. The electrode 30 is connected through terminal 32 to line 22 and potentiometer 14. The pressure sensitive cell 11 is constructed of materials having a coefficient of expansion that will compensate for the change in resistance of the carbon particles in the cell as the temperature is varied from hot to cold. "The resistance of the cell 11 is advantageously varied by pressure. At maximum compression of the cylinder to which a tube 24 is connected, the carbon particles will be most compactly arranged, thereby lowering the resistance in the part of the circuit containing these particles.

With reference again to FIG. 1, operation of the electrical ignition system of this invention will be de scribed. When the ignition'switch 5 is closed, current flows from thebattery 1 through lines 4, 3 and 17 to the primary winding 8 of transformer 7 and from the primary winding 8 through line 19, transistor 10 and lines 18 and 2 to battery '1. The current which is fiowing increases in the primary winding d of transformer 7 and reaches a maximum in a few thousandths of a second. During this short interval, a magnetic field is induced in the primary winding 8. When the piston 50 of the internal combustion engine reaches the upper end of its stroke, the resistance in the pressure sensitive cell 11 is reduced to such an extent, due to the high pres- ,sure, thatgthere is an increase in current flow through cell 11. The negative bias on transistor ltl is also in-' creased to the cut-off point, thereby causing the transistor 10 to stop conducting and the circuit to primary winding 8 of transformer 7 to be opened. The iron core 12 in the, transformer 7 is demagnetized, Causing the magnetic field to collapse. This sudden collapse induces voltage in both the primary winding 8 and secondary winding 9 of transformer 7. The many thousands of turns of wire in the secondary winding 9 cause sufiiciently high voltage to be induced in the secondary winding to force the current to jump across the .gap in the spark plug 6. The explosion resulting from the sparking of plug 6. forces'the piston 50 down. This relieves the pressure on pressure sensitive cell 11 and, at the same time, effects an increase in its resistance and a reduction in the negative bias on transistor 10 whereby current again flows negative bias voltage applied to transistor 1i through pressure sensitive cell 11 whereby current flow through the transistor 10 can be out off exactly at the point where the piston reaches the top of it's stroke or a few degrees before if this is required for maximum efficiency.

In another embodiment of the invention, a vacuum tube-type electronic valve is used in lieu of a transistor. 1

The circuit wherein the vacuum tube-type electronic valve is used is illustrated in FIG. 2. From a review of FIG. 2, it will be observed that all the other components of the individual ignition circuits for the spark plugs 6 are basically the same as for the embodiment employing secondary winding 9. Winding 9 produces a spark across the spark'pl-ug 6 in the manner previously de- 7 controlled by a negative bias applied through lines 4 V or 17 as the case maybe, potentiometer 14, line 22 pressure sensitive cell 11 and line 23. Thus, when the carbon particles 28 of any cell 11 are compressed due to the upward movement of the engine piston associated therewith, there will be an increase in current in the part of the circuit containing cell 11. This in turn increases the negative bias placed on grid 39 of the triode. When tube stops conducting as a result of the increase in the negative bias placed on igrid 39,'the circuit for the primary winding 8 is opened. The magnetic field in transformer 7 builds up and collapses, thereby inducing current in The induction "of current in associated therewith, all scribed. V v

ltt will be understood that various changes and modifications may be made to this inventionwithout departing, in the ap-" from the spirit'and scope thereof as defined pended claims, wherein V 1 former being directly connected to said electronic valve,

pressure sensitive means electrically connected to said source of potential and electrically connected directly to said electronic valve for controlling said electronic valve, and engine operated means for transmitting pressureto said pressure sensitive means so as to actuate said electronic valve and produce a fiow'of current in the secondary winding of the transformer andv a high potential to said spark plug, said pressure sensitive means being the only engine operated means employed to actuate said electronic valve.

2. The ignition system of cl-aim '1 wherein said ele c- V 1 tronic valve comprises a vacuum tube.

transistors and, accordingly, a detailed description of these circuits is not believed necessary. In the embodiment shown in FIG. 2, the vacuum tube-type electronic valve advantageously comprises a triode 35 provided with an anode 36, a cathode 37, a cathode heater 38, and a control grid 39. Grid .39 is connected to the cell 11,

cathode 37 is connected to the primary winding 8 of the transformer 7, and anode 36 is connected to the'line 2. The cathode heater 38 can be supplied with a low voltage by direct connection across battery ll.

While the individual ignition circuits of FIG. 2 are the same as for FIG. 1 in general, triodes require a higher voltage for operation than can be obtained from'a conventional automobile storage battery and, accordingly, a step-up power supply as shown in FIG. 2 to supply lines 2 and 3 would generally be employed. This power supply is a conventional power supply such as is em pl-oyed for powering automobile radio receives and, accordingly, it is not described in detail. In general, it comprises storage battery 1', filter 34, vibrator 40, transformer 41, rectifier 42 and an inductance coil 43. In the embodiment shown in FIG. 2, the rectifier 4,2 is a vacuum tube-type rectifier having a cathode 44, two anodes 45 and a cathode heater 46! The operation of such power supplies is well known and has been employed many times to power automotive radio receivers and, accordingly, such operation need not be described here. The operation of the circuit employing the triode 35 is the 3. The ignition system of claim 2 wherein said vacuum tube is a triode. r

4. An ignition system as set forth in claim 1 including a capacitor connected in parallel with said electronic valve.

5. The ignition system of claim 1 wherein said electronic valve comprises a transistor. f v

6. The ignition system of claim 1 wherein said internal combustion engine has a plurality of cylinders and a separate spark plug, electronic valve, transformer and pressure sensitive means for each cylinder. 7

7 An ignition system for an internal combustion engine having'at least one cylinder, said system comprising a source of potential, a spark plug for said cylinder, transformer means having primary and secondary windings for supplying a high voltage pulse from said source of potential to said spark .plug, thesecondary winding of said transformer means being connected to said spark plug, electronic valve means connected to the primary winding of said transformer means and adapted to control the flow of current from said source of potential to the primary winding of said transformer means, pressure sensitive cell means electrically connected to said source of potential and electrically connected directly to said electronic valve means for supplying and controlling a bias voltageon said electronic valve means, engine openated means for transmitting pressure from said cylinder to said pressure sensitive cell means whereby a predetermined pressure in the cylinder will cause said presure sensitive cell means to increase the bias voltage on said electronic valve means, and means connecting said electronic valve means to the pressure sensitive cell means whereby current flow through said electronic valve means to the primary windmg of the transformer means is cut off at the time an ignition 10. The ignition system of claim 7 wherein said elec tronic valve means comprises a transistor.

11. An ignition system for an internal combustion engine having at least one cylinder and a piston, said systemcomprising a source of potential, a spark plug for said cylinder, a transformer having primary and secondary windings for supplying a high voltage pulse from said source of potential to said spark plug, the secondary winding of said transformer being connected to said spark plug, electronic valve means connected to the primary winding of said transformer and adapted to control the flow of current from said source of potential to the primary Winding of said transformer, capacitor means connected in parallel with said electronic valve means, pressure sensitive cell means electrically connected to said source of potential and electrically connected directly to said electronic valve means for supplying and controlling a bias voltage on said electronic valve means, engine operated means including said piston for transmitting pressure from the cylinder to said pressure sensitive cell means whereby a predetermined pressure in the cylinder causes said pressure sensitive cell means to increase the bias voltage on said electronic valve means and out off the flow of current through said electronic valve means to the primary winding of the transformer at the time an ignition spark is needed, the cutting oif of the flow of current to said primary winding in turn inducing a high voltage pulse in said secondary winding and a sparking of said spark plug, and means for adjusting said bias voltage whereby said electronic valve means will be cut off at the time said piston reaches the point in the cylinder where the spark is neededsaid pressure sensitive cell means being the only engine operated means employed to increase the bias a voltage on saidelectronic valve; I

12. The ignition system as set forth in claim 11 where- V References Cited in the file of this patent UNITED STATES PATENTS 1,020,503 Holden Mar. 19, 1912 1,679,159 French July 31, 1928 2,474,550 Short June 28, 1949 2,852,590 =Fremon Sept. 16, 1958 2,918,913 Guiot Dec. 29, 1959 

1. AN IGNITION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE HAVING AT LEAST ONE CYLINDER, SAID SYSTEM COMPRISING A SOURCE OF POTENTIAL, A SPARK PLUG FOR SAID CYLINDER, MEANS INCLUDING AN ELECTRONIC VALVE AND A TRANSFORMER FOR SUPPLYING A HIGH POTENTIAL TO SAID SPARK PLUG, THE SECONDARY WINDING OF SAID TRANSFORMER BEING DIRECTLY CONNECTED TO SAID SPARK PLUG AND THE PRIMARY WINDING OF SAID TRANSFORMER BEING DIRECTLY CONNECTED TO SAID ELECTRONIC VALVE, PRESSURE SENSITIVE MEANS ELECTRICALLY CONNECTED TO SAID SOURCE OF POTENTIAL AND ELECTRICALLY CONNECTED DIRECTLY TO SAID ELECTRONIC VALVE FOR CONTROLLING SAID ELECTRONIC VALVE, AND ENGINE OPERATED MEANS FOR TRANSMITTING PRESSURE TO SAID PRESSURE SENSITIVE MEANS SO AS TO ACTUATE SAID ELECTRONIC VALVE AND PRODUCE A FLOW OF CURRENT IN THE SECONDARY WINDING OF THE TRANSFORMER AND A HIGH POTENTIAL TO SAID SPARK PLUG, SAID PRESSURE SENSITIVE MEANS BEING THE ONLY ENGINE OPERATED MEANS EMPLOYED TO ACTUATE SAID ELECTRONIC VALVE. 